Abstract TMP97: Comparison Of Severity And Mortality Among Patients With Atrial Fibrillation Who Developed Ischemic Stroke During Anticoagulation With Warfarin And Non-vitamin K Antagonist Oral Anticoagulants

Introduction: Non-vitamin K antagonist oral anticoagulant (NOAC) has been the drug of choice for preventing ischemic stroke in patients with atrial fibrillation since 2014. In previous studies, the stroke risk while taking warfarin was known to be 2 per 100 patient-years and 1.5% per year while taking NOACs. We hypothesized that even if ischemic stroke occurred during anticoagulation therapy with NOACs, the prognosis was likely to be better than that of warfarin. Methods: We obtained data from the nationwide claim database from 2009 to 2019. Patients with atrial fibrillation were identified using the International Classification of Disease Codes. After the diagnosis of atrial fibrillation, patients who developed ischemic stroke during anticoagulation were extracted. The severity of ischemic stroke in the patients was evaluated by the stroke severity index (SSI) calculated by the combination of claim codes. Patients who died within 3-months and within 1-year after ischemic stroke were identified. The patients were divided according to the drug of anticoagulation (warfarin, dabigatran, apixaban, rivaroxaban, edoxaban). Results: A total of 206,848 patients who were newly diagnosed with atrial fibrillation and started anticoagulation therapy were analyzed. Among them, 10,658 patients developed ischemic stroke during follow-up. The anticoagulants administered to these patients were warfarin in 4,423, dabigatran in 965, apixaban in 2,320, rivaroxaban in 1,702, and edoxaban in 1,248. The SSI was highest in the warfarin group (11.43±3.85), and lower in the edoxaban group (8.93±4.03). The order of mortality at 3-months after ischemic stroke was warfarin (17.88%), rivaroxaban (12.34%), dabigatran (9.53%), apixaban (8.28%), and edoxaban group (8.25%). The 1-year mortality rate also showed the same trend. Among NOACs, apixaban had the lowest hazard ratio (HR), HR for 3-months mortality was 0.431 (95% CI 0.367-0.505, p<0.0001), and HR for 1-year mortality was 0.455 (95% CI 0.407-0.510, p<0.0001). Conclusions: In our study, we confirmed that NOAC could lower the risk of death from ischemic stroke than warfarin in patients with atrial fibrillation. Except for rivaroxaban, there was no difference in mortality in the other three NOAC groups.